Principal Results: I: Synthesis and study of improved fluorescence indicators tailored for laser confocal microscopy: (Hagins, Yoshikami, Rice, Whittaker) A chromophore based on a known laser dye has been developed with the following useful properties: a) Narrow absorption with high extinction centered at 532 nm, the emission line of frequency-doubled Nd-YAG lasers. b) High fluorescence efficiency with a small Stokes shift, narrow fluorescence emission bandwith and great resistence to photobleaching and metabolic degradation. c) Ready adaptability to chemical coupling with a variety of functional groups that can facilitate probing of cellular environments and binding sites. d) Small size, weak non-specific binding to cellular components and ready permeation through lipid portions of cell membranes. So far, four derivatives have been prepared to function as intracellular potential probes, probes of hydrophobic regions, and precursors for labels to study drug-binding sites in cells and tissues.